Hand Embroidery | Button Hole Stitch:
Buttonhole stitches catch a loop of the thread on the surface of the fabric and needle is returned to the back of the fabric at a right angle to the original start of the thread.
buttonhole stitches are used to make stems in crewel embroidery, to make sewn eyelets, to attach applique to ground fabric, and as couching stitches. Buttonhole stitch scallops, usually raised or padded by rows of straight or chain stitches, were a popular edging in the 19th century.
Buttonhole stitches are also used in cutwork, including Broderie Anglaise, and form the basis for many forms of needlelace.